Terahertz Imaging of Drug Products

Ulmschneider, Michel

doi:10.1002/9783527678136.ch10

Cited by 2 publications

(2 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A terahertz photoelastic image (Figure 7b) that mimics the visible photoelastic image of Figure 7a was generated according to Equation ( 7) on a pixel-by-pixel basis by multiplying images of the relative birefringence (Figure 7d), the time delay through the sample (which is a measure of the thickness, L, of the sample), and the sin(θ + θ o ) cos(θ + θ o ) factor, which was determined by the stress direction (Figure 7c). The terahertz power is proportional to the square of Equation (7). The resulting image was plotted in Figure 7b as a contour plot.…”

Section: Discussionmentioning

confidence: 99%

“…Terahertz wavelengths (3 mm to 100 µm) are in the electromagnetic spectral band between microwave and infrared light. Recent NDE applications include composite structures [2], additive manufacturing [3], the agricultural-food industry [4][5][6], pharmaceutical products [7], and moisture monitoring [8]. Terahertz radiation may be used for the nondestructive imaging of materials such as plastics, ceramics, and other dielectrics since these materials tend to exhibit relatively small absorbance in the terahertz range, enabling the imaging of the internal structure as well as defects/ inclusions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Fossil Amber Birefringence and Inclusions Using Terahertz Time-Domain Spectroscopy

et al. 2022

View full text Add to dashboard Cite

Using a cross-polarization transmission geometry, stress maps for the normalized birefringence and intrinsic stress direction of polymeric materials may be obtained using terahertz nondestructive evaluation. The analysis method utilizes a deconvolution method to determine the arrival times and amplitude of the cross-polarized terahertz pulses through a birefringent material. Using amber (a naturally occurring polymer) as a material of interest, stress maps show that inclusion-free Lebanese amber samples behave as classic uniaxial birefringent (photoelastic) materials whose principal stress directions, as inferred in the terahertz spectral range, agree well with visible photoelasticity measurements. Since amber samples, depending upon their source, may be either transparent or opaque to visible light, comparing birefringence measurements in the visible and terahertz spectral ranges cross-validates the stress measurements, thereby establishing a strong and unique stress analysis methodology for visibly opaque samples. While the material of interest for this paper is amber, the method is generally applicable for any terahertz-transparent polymer. The cross-polarization experimental configuration enables stress levels within the amber matrix to be visualized while also outlining highly localized regions of stress surrounding inclusions. Birefringence stress maps clearly show localized increases in stress magnitude and directional changes surrounding inclusions.

show abstract

Section: Discussionmentioning

confidence: 99%